CN106024565A - Plasma processing apparatus and plasma processing method - Google Patents

Abstract

A plasma processing device comprising: a reaction chamber; a plasma generating unit for generating plasma in the reaction chamber; a workbench arranged inside the reaction chamber and carrying a transport carrier having a substrate, a holding sheet and a frame; The electrostatic adsorption mechanism of the electrode part; the support part that supports the conveyance carrier between the loading position on the workbench and the handover position where the workbench is separated upward; and the support part that makes the support part rise and fall relative to the workbench. When mounted on the table, 1) After the outer peripheral part of the holding sheet is in contact with the table, the electrostatic adsorption mechanism applies a voltage to the electrode part. The application of the voltage includes the operation of increasing or decreasing the absolute value of the voltage. After the above operation is completed, or 2) After the holding piece comes into contact with the workbench, the lifting mechanism raises and lowers the support part for more than one time in the vicinity of the workbench. After the lifting and lowering of the support part is completed and the outer periphery of the holding piece contacts the workbench, the plasma generating part generates Plasma.

Description

Plasma processing device and plasma processing method

technical field

The present invention relates to a plasma processing device and a plasma processing method, and more specifically, to a plasma processing device and a plasma processing method for processing a substrate held on a transport carrier.

Background technique

As a method of dicing a substrate, known is plasma dicing in which a substrate on which a resist mask is formed is diced into individual chips by plasma etching. Patent Document 1 teaches that in order to improve the good operability of substrates during transportation, etc., in a state where the substrate is attached to a transportation carrier provided with a frame and a holding sheet covering its opening, the substrate is mounted on a workbench (hereinafter, there is simply referred to as a working table). In the case of the station), plasma treatment is performed.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2009-94436

In the case where the substrate is mounted on a stage while being held on a conveyance carrier to perform plasma processing, the conveyance carrier is generally attracted to the stage by an electrostatic adsorption mechanism called an electrostatic chuck. The electrostatic chuck mechanism applies a voltage to the electrostatic chuck (Electrostatic Chuck) electrode (hereinafter referred to as the ESC electrode) arranged inside the table, and the Coulomb force acting between the ESC electrode and the transport carrier, Johansen Rabeck Force, so that the transport carrier is adsorbed on the workbench. The workbench is cooled. By performing the plasma treatment in a state where the transport carrier is adsorbed to the cooled stage, the transport carrier during the plasma treatment can be effectively cooled.

In recent years, electronic equipment has been reduced in size and thickness, and the thickness of IC chips and the like mounted in the electronic equipment has become smaller. Accompanied by this, the thickness of the substrate for forming the IC chip or the like to be diced is also reduced, and the substrate tends to be warped.

In addition, the thickness of the holding sheet holding the substrate is also small, and it is easy to bend. As a result, the transport carrier holding the substrate may be placed on the stage with the holding sheet wrinkled. Wrinkles are not eliminated even if the transport carrier is adsorbed to the table by the electrostatic adsorption mechanism. If the plasma treatment is performed with wrinkles remaining in the holding sheet, an abnormal discharge will occur at the wrinkled portion or the temperature of the wrinkled portion will rise, making normal plasma treatment difficult.

Contents of the invention

One aspect of the present invention relates to a plasma processing apparatus that performs plasma processing on a substrate held on a transport carrier. The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, and the substrate is held by the holding sheet. The plasma processing apparatus includes: a reaction chamber; a plasma generation unit that generates plasma in the reaction chamber; a workbench disposed inside the reaction chamber for carrying a transport carrier; an electrostatic adsorption mechanism that is provided inside the workbench. The electrode part; the support part, which supports the conveyance carrier between the loading position on the workbench and the transfer position separated from the workbench upward; and the lifting mechanism, which makes the support part rise and fall relative to the workbench. When the transport carrier is mounted on the table, the electrostatic adsorption mechanism applies a voltage to the electrode portion after the outer peripheral portion of the holding sheet comes into contact with the table. At this time, the application of the voltage includes an operation of increasing or decreasing the absolute value of the voltage, and the plasma generation unit generates plasma after the operation is completed.

Another aspect of the present invention relates to a plasma processing method in which a carrier holding a substrate is mounted on a table of a plasma processing apparatus to perform plasma processing on the substrate. The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, and the substrate is held by the holding sheet. The plasma processing method includes: a step of supporting the transport carrier on a support part that can be raised and lowered relative to the work table at a transfer position separated from the work table upward; ; and a step of applying a voltage to the electrode portion of the electrostatic adsorption mechanism provided inside the table. The step of applying a voltage to the electrode portion includes an operation of increasing or decreasing the absolute value of the voltage after the outer peripheral portion of the holding sheet comes into contact with the table, and performing plasma treatment after the operation is completed.

Another aspect of the present invention relates to a plasma processing apparatus for performing plasma processing on a substrate held on a transport carrier. The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, and the substrate is held by the holding sheet. The plasma processing apparatus includes: a reaction chamber; a plasma generating unit that generates plasma in the reaction chamber; a workbench disposed inside the reaction chamber for carrying a transport carrier; an electrostatic adsorption mechanism having a An electrode part; a support part that supports the conveyance carrier between a mounting position on the table and a handover position detached upward from the table; and an elevating mechanism that raises and lowers the support part relative to the table. In the case of loading the transport carrier on the workbench, after the holding piece comes into contact with the workbench, the elevating mechanism is near the workbench to raise or lower the support part for more than one time, and after the rise and fall of the support part are completed, and After the outer peripheral portion of the holding sheet comes into contact with the table, the plasma generation unit generates plasma.

Another aspect of the present invention relates to a plasma processing method in which a carrier holding a substrate is mounted on a table of a plasma processing apparatus to perform plasma processing on the substrate. The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, and the substrate is held by the holding sheet. The plasma processing method includes: a step of supporting the transport carrier on a support part that can be raised and lowered with respect to the work table at a transfer position separated upward from the work table; and a step of lowering the support part to mount the transfer carrier at a mounting position on the work table ; and a step of applying a voltage to the electrode portion of the electrostatic adsorption mechanism provided inside the table. The process of loading the conveying carrier includes: after the holding piece is in contact with the workbench, the support part is raised and lowered more than once in the vicinity of the workbench, and after the rise and fall of the support part are completed, the outer peripheral part of the holding piece is in contact with the workbench. After contacting the stages, plasma treatment is performed.

According to the present invention, when plasma processing is performed on a substrate held on a transport carrier, the yield of products is improved.

Description of drawings

Fig. 1 is a plan view (a) schematically showing a transport carrier holding a substrate used in an embodiment of the present invention and a cross-sectional view (b) thereof along line B-B.

FIG. 2 is a schematic diagram of a plasma processing apparatus according to an embodiment of the present invention.

3 is a schematic diagram showing the relationship between the ESC electrode and the DC power supply according to the embodiment of the present invention.

4 is a schematic graph in which the time from when the support portion starts to fall according to the first embodiment of the present invention is taken as the abscissa, and the voltage applied to the ESC electrode is taken as the ordinate.

FIG. 5 is an explanatory view showing bending of the holding piece according to the first embodiment of the present invention.

6A is a schematic diagram ((a) to (d)) showing the state from when the support unit according to the first embodiment of the present invention starts to descend until the conveyance carrier is mounted on the table.

FIG. 6B is a schematic diagram ((a) to (d)) showing the state of the variation application I according to the first embodiment of the present invention.

7 is a schematic diagram ((a) to (e)) showing a part of the operation of the plasma processing apparatus according to the first embodiment of the present invention.

8 is a schematic graph ((a) with the time from the first high-frequency power supply according to the first embodiment of the present invention inputting power to the antenna as the abscissa and the voltage applied to the ESC electrode as the ordinate. and (b)); a schematic graph (c) with the same time as the horizontal axis and the vertical axis as the power input to the antenna.

9 is a schematic graph in which the time from when the support portion starts to fall according to the second embodiment of the present invention is taken as the abscissa, and the voltage applied to the ESC electrode is taken as the ordinate.

10 is a schematic graph in which the time from when the support portion starts to fall according to the third embodiment of the present invention is taken as the abscissa, and the voltage applied to the ESC electrode is taken as the ordinate.

Fig. 11 shows a schematic graph (a) in which the time from when the supporting portion according to the fourth embodiment of the present invention begins to fall is taken as the abscissa, and the voltage applied to the ESC electrode is taken as the ordinate, and the same time as The horizontal axis is a schematic graph (b) whose vertical axis is the distance T between the upper end surface of the support part and the table.

12A is a schematic diagram ((a) to (d)) showing the state from when the support unit according to the fourth embodiment of the present invention starts to descend until the conveyance carrier is mounted on the table.

FIG. 12B is a schematic diagram ((a) to (d)) showing the state of the lifting operation according to the fourth embodiment of the present invention.

13 is a schematic diagram ((a) to (e)) showing part of the operation of the plasma processing apparatus according to the fourth embodiment of the present invention.

14 shows a schematic graph (a) in which the time from when the supporting portion according to the fifth embodiment of the present invention begins to fall is taken as the abscissa, and the voltage applied to the ESC electrode is taken as the ordinate, and the same time as The horizontal axis is a schematic graph (b) whose vertical axis is the distance T between the upper end surface of the support part and the table.

Fig. 15 shows a schematic graph (a) with the time when the support portion starts to fall according to the sixth embodiment of the present invention as the horizontal axis and the voltage applied to the ESC electrode as the vertical axis, and the same time as The horizontal axis is a schematic graph (b) whose vertical axis is the distance T between the upper end surface of the support part and the table.

-Symbol Description-

1: Substrate, 2: Frame, 2a: Notch, 2b: Chamfer, 3: Holder, 3a: Adhesive surface, 3b: Non-adhesive surface, 3c: Perimeter, 10: Carrier, 100: Plasma treatment Device, 103: vacuum chamber, 103a: gas inlet, 103b: exhaust port, 108: dielectric member, 109: antenna (plasma source), 110A: first high-frequency power supply, 110B: second high-frequency power supply, 111: workbench, 112: process gas source (gas supply means), 113: ashing gas source, 114: decompression mechanism, 115: electrode layer, 116: metal layer, 117: support layer, 118: peripheral part, 119: ESC Electrode, 120: high-frequency electrode, 121: lifting rod, 122: supporting part, 122a: upper end surface, 123A, 123B: lifting mechanism, 124: outer cover, 124W: window part, 125: refrigerant circulation device, 126: DC power supply , 127: refrigerant flow path, 128: control device

detailed description

Hereinafter, the present invention will be described in detail with reference to the drawings showing one embodiment of the present invention.

Fig. 1 (a) is a top view schematically showing a transport carrier 10 used in an embodiment of the present invention, and Fig. 1 (b) is a view at the line B-B shown in (a) of the transport carrier 10 in an unloaded state. Sectional view. In addition, in FIG. 1, the case where the frame 2 and the board|substrate 1 are both circular is illustrated, but it is not limited to this.

As shown in FIG. 1( a ), the transport carrier 10 includes a frame 2 and a holding piece 3 for holding the substrate 1 . The outer peripheral portion 3 c of the holding piece 3 is fixed to the frame 2 . The substrate 1 is bonded to the holding sheet 3 and held on the transport carrier 10 . The outer peripheral portion 3 c is a portion where the holding piece 3 overlaps the frame 2 . In FIGS. 1( a ) and ( b ), the outer peripheral portion 3 c is hatched for convenience.

The substrate 1 is an object to be processed by plasma processing such as plasma cutting. The substrate 1 is formed by forming a circuit layer such as a semiconductor circuit, an electronic component element, MEMS, etc. on one surface of the substrate main body (for example, Si, GaAs, SiC), and then grinding the back surface of the substrate main body opposite to the circuit layer. To make it thinner and made. The thickness of the substrate 1 is usually very thin, about 25 to 150 μm. Therefore, the substrate 1 itself has substantially no self-supporting property (rigidity). When the thickness of the substrate 1 becomes thin, warping or bending may occur due to a difference in internal stress between the circuit layer portion and the substrate main body portion. If warping or bending occurs, it will be difficult to carry out conveyance, cooling, and the like of the substrate 1 when plasma processing is performed.

Therefore, the outer peripheral portion 3 c of the holding sheet 3 is fixed to the substantially flat frame 2 in a state where tension is applied, and the substrate 1 is bonded to the holding sheet 3 . The holding sheet 3 is made of resin with a thickness of about 50 to 150 μm, and has rigidity to the extent that it can hold the substrate 1 . In addition, an adhesive layer is formed on one surface of the holding sheet 3, and the substrate 1 is bonded to the adhesive layer. Thereby, the conveyance carrier 10 can hold the board|substrate 1, the holding piece 3, and the frame 2 in substantially the same plane. Therefore, when plasma processing is performed on the substrate 1 , operations such as conveyance of the substrate 1 and cooling during the plasma processing become easy.

However, if the substrate 1 is bonded to the holding piece 3 fixed to the frame 2 by bonding the outer peripheral portion 3c, the holding piece 3 may bend (see FIG. 1( b )). In addition, in FIG. 1( b ), in order to facilitate understanding of the description, the curve is emphasized and illustrated.

The following four cases are conceivable as the cause of the bending of the holding piece 3 .

The first case is that the holding piece 3 is bent due to the deformation of the frame 2 . Although the frame 2 is originally designed to be flat, the flatness may be low due to variations and tolerances when manufacturing the frame 2 , repeated use in the production process, and the like. If the frame 2 with low flatness is used, the holding piece 3 fixed to the frame 2 will bend.

The second case is a case where the holding piece 3 is warped due to the shape of the substrate 1 . Although the transport carrier 10 holds the substrate 1 almost flat by the tension of the holding sheet 3, for example, if the substrate 1 has a notch such as an orientation flat, the tension of the holding sheet 3 cannot be uniformly applied to the substrate 1. . In this case, wrinkles are generated in the holding sheet 3 in the vicinity of the orientation plane, which becomes bending of the holding sheet 3 .

The third case is a case where the holding piece 3 bends due to gravity. Although the transport carrier 10 holds the substrate 1 almost flat by the tension of the holding sheet 3, due to the weight of the substrate 1 and the holding sheet 3, the holding sheet 3 is stretched or the frame 2 is deformed, and the holding sheet 3 is bent. .

The fourth case is a case where the holding piece 3 is warped due to the stress of the substrate 1 . Stress that warps the substrate 1 is applied to the substrate 1 . On the other hand, the holding sheet 3 resists the stress by the adhesive force of the bonded substrate 1 and the tension of the holding sheet 3 , suppresses the bending of the substrate 1 and holds the substrate 1 flat. At this time, if the stress on the substrate 1 is greater, the holding sheet 3 cannot suppress the bending of the substrate 1 , and the holding sheet 3 is stretched and bent.

Electrodes for electrostatic adsorption (ESC electrodes) are roughly classified into two types, unipolar type and bipolar type. By applying a voltage to the ESC electrodes, an adsorption force is generated between the ESC electrodes and the holding sheet 3 , so that the transport carrier 10 can be adsorbed on the table 111 .

A unipolar ESC electrode is composed of at least one electrode, and a voltage of the same polarity is applied to all the electrodes. The electrostatic adsorption mechanism equipped with a unipolar ESC electrode utilizes Coulomb force as an adsorption mechanism. By applying a voltage to all the electrodes, charges due to dielectric polarization are induced on the surface of the stage 111 made of the dielectric, and the transport carrier 10 placed on the stage 111 is charged. As a result, a Coulomb force acts between the charge induced on the surface of the table 111 and the charged carrier 10 , and the carrier 10 is attracted to the table 111 . In addition, in order to charge the transport carrier 10 , it is only necessary to generate plasma in the reaction chamber 103 and to expose the transport carrier 10 to the generated plasma.

On the other hand, a bipolar ESC electrode includes a positive electrode and a negative electrode, and voltages of different polarities are applied to the positive electrode and the negative electrode. As a bipolar ESC electrode, for example, a comb electrode 119 as shown in FIG. 3 is used. As shown in Figure 3, a voltage of V1 is applied to the positive electrode, and a voltage of -V1 is applied to the negative electrode.

There are cases where Coulomb force is used as the adsorption mechanism of the electrostatic adsorption mechanism provided with bipolar ESC electrodes, and cases where Johnson-Rahbek force is used. According to the adsorption mechanism, the structure of the electrode and the material (for example, ceramics) constituting the electrode are appropriately selected. In the case of any adsorption mechanism, an adsorption force can be generated between the ESC electrode and the transport carrier 10 by applying voltages with different polarities to the positive electrode and the negative electrode, so that the transport carrier 10 is adsorbed on the workbench 111 . In addition, in the case of the bipolar type, unlike the case of the unipolar type, it is not necessary to charge the transport carrier 10 for adsorption.

A bipolar electrode can function as a unipolar electrode by applying a voltage to the positive electrode and the negative electrode. Specifically, by applying a voltage of the same polarity to the positive electrode and the negative electrode, it can be used as a unipolar ESC electrode. Hereinafter, the application of voltages of different polarities to the positive and negative electrodes of the bipolar electrodes is referred to as bipolar mode, and the application of voltages of the same polarity to the positive and negative electrodes is referred to as unipolar mode.

In the case of the unipolar mode, a voltage of the same polarity is applied to the positive electrode and the negative electrode, and Coulomb force is used as an adsorption mechanism. Unlike the case of the bipolar mode, when a voltage is applied only to the positive electrode and the negative electrode, the transport carrier 10 cannot be adsorbed. In the monopolar mode, in order to adsorb the transport carrier 10 , it is necessary to charge the transport carrier 10 . Therefore, when adsorbing in the monopolar mode, the transport carrier 10 is charged by generating plasma in the reaction chamber 103 and exposing the transport carrier 10 to the plasma. As a result, the transport carrier 10 is adsorbed on the table 111 . The unipolar and bipolar ESC electrodes have been described above, but the transport carrier 10 can be adsorbed to the stage 111 using any type.

As described above, when the transport carrier 10 in the bent state of the holding sheet 3 is mounted on the table 111, the holding sheet 3 and the substrate 1 themselves may be wrinkled in some cases. Such wrinkles may occur in a region of the holding sheet 3 not in contact with the substrate 1 or in a region of the holding sheet 3 in contact with the substrate 1 . In the latter case, wrinkles may also be generated in the substrate 1 itself bonded to the holding sheet 3 .

In addition, the transport carrier 10 is usually heated by plasma irradiation, and the table 111 is cooled to, for example, 15° C. or lower in order to suppress damage by heat. By cooling the table 111, the transportation carrier 10 mounted on the table 111 is also cooled, and the thermal damage of the transportation carrier 10 is suppressed. However, when the holding sheet 3 comes into contact with the cooled table 111, the holding sheet 3 may shrink. Since the outer peripheral portion 3 c of the holding sheet 3 is fixed to the frame 2 , shrinkage of the holding sheet 3 can be one of causes of wrinkling of the holding sheet 3 .

If the wrinkled transport carrier 10 is adsorbed to the workbench 111 by an electrostatic adsorption mechanism, at least a part of the wrinkles generated in the holding sheet 3 cannot be in contact with the workbench 111, and the holding sheet 3 is partially detached from the workbench 111. is adsorbed. In the case where such a detachment occurs in the region of the holding sheet 3 that is in contact with the substrate 1, if the plasma treatment is performed directly, the etching will become uneven between the detachment and other parts, resulting in deviations in the processed shape and untreated portions. . In addition, no matter where the detached portion of the holding sheet 3 is located, the detached portion may have a local temperature rise and abnormal discharge may occur. There is also a concern that the substrate 1, the holding sheet 3, and the ESC electrodes may be damaged due to the temperature rise and the abnormal discharge. In addition, in the pick-up process after the plasma treatment, since the holding sheet 3 has wrinkles, it is difficult to identify the chip accurately, and a pick-up error may occur. Also in the subsequent appearance inspection process, it may not be possible to accurately discriminate between a good product and a non-defective product.

In the first to third embodiments of the present invention, when the holding sheet 3 is adsorbed to the table 111, the voltage applied to the ESC electrode 119 is changed so that the holding sheet 3 is adsorbed without wrinkles. on workbench 111.

Furthermore, in the fourth to sixth embodiments of the present invention, when the conveyance carrier 10 is mounted on the table 111, the conveyance carrier 10 is raised and lowered on the table 111 so that the holding sheet 3 is free from wrinkles. Adhered to the workbench in the state.

(Plasma treatment device)

First, plasma processing apparatus 100 according to the embodiment of the present invention will be described with reference to FIG. 2 . FIG. 2 schematically shows a cross section of plasma processing apparatus 100 according to an embodiment of the present invention.

The plasma processing apparatus 100 includes a table 111 . The transport carrier 10 is mounted on the table 111 so that the surface of the holding sheet 3 holding the substrate 1 (adhesive surface 3 a ) faces upward. A cover 124 having a window portion 124W for covering at least a part of the frame 2 and the holding sheet 3 and exposing at least a part of the substrate 1 is disposed above the table 111 .

The stage 111 and the cover 124 are arranged in the reaction chamber (vacuum chamber) 103 . The top of the vacuum chamber 103 is closed by a dielectric member 108 , and an antenna 109 as an upper electrode is disposed above the dielectric member 108 . The antenna 109 is electrically connected to the first high-frequency power source 110A. The table 111 is arranged on the bottom side in the vacuum chamber 103 .

The vacuum chamber 103 is connected to the gas introduction port 103a. The gas introduction port 103a is connected to a process gas source 112 and an ashing gas source 113 which are supply sources of a gas for plasma generation, respectively, through pipes. In addition, the vacuum chamber 103 is provided with an exhaust port 103b, and the exhaust port 103b is connected to a decompression mechanism 114 including a vacuum pump for evacuating and depressurizing the gas in the vacuum chamber 103 . The plasma generation part is comprised from the antenna 109, the process gas source 112, and 110 A of 1st high-frequency power supplies.

The table 111 includes a substantially circular electrode layer 115 , a metal layer 116 , a base 117 supporting the electrode layer 115 and the metal layer 116 , and an outer peripheral portion 118 surrounding the electrode layer 115 , the metal layer 116 , and the base 117 . Inside the electrode layer 115 are arranged an electrode section (hereinafter, referred to as an ESC electrode) 119 constituting an electrostatic adsorption mechanism, and a high-frequency electrode section 120 electrically connected to the second high-frequency power supply 110B. The ESC electrode 119 is electrically connected to a DC power source 126 . The electrostatic adsorption mechanism is composed of an ESC electrode 119 and a DC power supply 126 .

The metal layer 116 is made of, for example, aluminum whose surface is covered with alumite. A refrigerant flow path 127 is formed in the metal layer 116 . The refrigerant flow path 127 cools the table 111 . As the table 111 is cooled, the conveyance carrier 10 mounted on the table 111 is cooled, and a part of the cover 124 that is in contact with the table 111 is also cooled. Refrigerant in refrigerant flow path 127 is circulated by refrigerant circulation device 125 .

In the vicinity of the outer periphery of the table 111, a plurality of support portions 122 penetrating the table 111 are arranged. The supporting part 122 is driven to lift up and down by the lift mechanism 123A. When the upper end surface 122 a of the support part 122 is at the delivery position above the workbench 111 , the delivery carrier 10 is transported into the vacuum chamber 103 by a delivery mechanism not shown, and delivered to the support part 122 . At this time, the support portion 122 supports the frame 2 of the transport carrier 10 . More preferably, the support portion 122 supports the overlapping portion of the frame 2 of the transport carrier 10 and the holding piece 3 (outer peripheral portion 3 c of the holding piece 3 ). When the upper end surface 122a of the support part 122 is lowered below the same level as the surface of the table 111, the conveyance carrier 10 is mounted on the predetermined position of the table 111. As shown in FIG.

In addition, in the case of the fourth embodiment to the sixth embodiment, when the transport carrier 10 is mounted on the table 111, the upper end surface of the support portion 122 is raised and lowered at least once in the vicinity of the table 111 by the elevating mechanism 123A. . The vicinity of the table 111 refers to the distance from the transfer position to the mounting position of the transport carrier 10 , for example, 0.1 mm to 5 mm from the surface of the table 111 to the upper side. Hereinafter, the operation of raising and lowering again in the vicinity of the table 111 during the lowering of the support portion 122 from the transfer position to the loading position is referred to as the raising and lowering operation M.

One end of the cover 124 is connected to a plurality of elevating rods 121 so that the cover 124 can be raised and lowered. The elevating rod 121 is driven to elevate by an elevating mechanism 123B. The lifting operation of the lifting mechanism 123B can be performed independently of the lifting mechanism 123A.

The control device 128 controls the actions of the elements constituting the plasma processing apparatus 100, wherein the plasma processing apparatus 100 includes: a first high-frequency power supply 110A, a second high-frequency power supply 110B, a process gas source 112, an ashing gas source 113, a reducing Compression mechanism 114, refrigerant cycle device 125, lifting mechanism 123A, lifting mechanism 123B and electrostatic adsorption mechanism.

(frame)

The frame 2 is a frame body having an opening having an area equal to or greater than that of the entire substrate 1, and has a predetermined width and a substantially constant thin thickness. The frame 2 holds the holding sheet 3 and the substrate 1 and has rigidity to a degree that can be transported.

The shape of the opening of the frame 2 is not particularly limited, for example, it may be a polygon such as a circle, a rectangle, or a hexagon. Notches 2a, cut corners 2b and the like for positioning may also be provided on the frame 2 . As a material of the frame 2, metals, such as aluminum and stainless steel, resin, etc. are mentioned, for example. On one surface of the frame 2, a part of the one surface 3a of the outer peripheral portion 3c of the holding piece 3 is bonded.

(hold sheet)

The holding sheet 3 includes, for example, a surface with an adhesive (adhesive surface 3 a ) and a surface without an adhesive (non-adhesive surface 3 b ). A part of the adhesive surface 3 a of the outer peripheral portion 3 c is adhered to one surface of the frame 2 . In addition, the substrate 1 is bonded to the portion exposed from the opening of the frame 2 on the bonding surface 3a. The adhesive surface 3 a is preferably composed of an adhesive component whose adhesive force is reduced by irradiation of ultraviolet rays. This is because, by irradiating with ultraviolet rays after dicing, the separated substrates (chips) are easily peeled off from the adhesive surface 3a, thereby facilitating picking. For example, the holding sheet 3 may be composed of a UV-curable acrylic adhesive (adhesive surface 3 a ) and a base material made of polyolefin (non-adhesive surface 3 b ). In this case, the thickness of the UV-curable acrylic adhesive is preferably 5 to 20 μm, and the thickness of the base material made of polyolefin is 50 to 150 μm.

The holding sheet 3 may also be electrically conductive. In the case of a unipolar ESC electrode or a bipolar ESC electrode operating in a unipolar mode, a high adsorption force to the stage 111 can be obtained regardless of whether the holding sheet 3 is conductive or not. On the other hand, in the case of the ESC electrode operating in the bipolar mode, if the conductivity of the holding sheet 3 is insufficient, the adsorption force to the table 111 becomes weak. Therefore, the conductive holding sheet 3 is particularly useful when operating a bipolar ESC electrode in a bipolar mode. Accordingly, when the bipolar ESC electrode is operated in the bipolar mode, it is possible to increase the adsorption force with respect to the table 111 .

(substrate)

The substrate 1 is an object to be plasma-treated, and is not particularly limited. The material of the substrate 1 is also not particularly limited. For example, it may be a semiconductor, a dielectric, a metal, or a laminate thereof. Examples of semiconductors include silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), silicon carbide (SiC), and the like. In addition, examples of the dielectric include silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), polyimide, lithium tantalate (LiTaO ₃ ), lithium niobate (LiNbO ₃ ), and the like. Its size is also not particularly limited, for example, the maximum diameter is about 50 mm to 300 mm, and the thickness is about 25 to 150 μm. In addition, the shape of the substrate 1 is not particularly limited, and is, for example, circular or angular. Orientation flats, notches, and other cutouts (both not shown) may also be provided on the substrate 1 .

In addition, a resist mask is formed into a desired shape (not shown) on the surface of the substrate 1 that is not bonded to the holding sheet 3 . The portion where the resist mask is formed is protected from plasma-based etching. The portion where the resist mask is not formed can be plasma-etched from the front to the back.

(Electrostatic adsorption mechanism)

The electrostatic adsorption mechanism applies a voltage from a DC power supply 126 to the ESC-type electrode 119 disposed inside the table 111 (electrode layer 115 ), and passes Coulomb force and Johansen-Rabeck force moving between the table 111 and the transport carrier 10 . , making the transport carrier 10 adsorb on the workbench 111 . The ESC electrode 119 is arranged such that its center almost coincides with the center of the table 111 . In addition, the center of the ESC electrode 119 can be regarded as the center of the perfect circle when the smallest perfect circle containing the entire ESC electrode 119 is drawn.

The ESC electrode 119 may be bipolar or unipolar. In addition, the bipolar ESC electrode 119 can be operated in a bipolar mode or a unipolar mode. When the ESC electrode 119 is a unipolar type or operates in a unipolar mode, the DC power supply 126 and the first high-frequency power supply 110A are activated to attract the transport carrier 10 to the table 111 . Specifically, the first high-frequency power supply 110A is started to work to generate plasma in the reaction chamber 103, the surface of the transport carrier 10 is charged and the DC power supply 126 is started to work, and the ESC electrode 119 of the unipolar or unipolar mode is charged. A voltage is applied to generate an adsorption force between the transport carrier 10 and the table 111 .

When the ESC electrode 119 is a bipolar type and operates in a bipolar mode, the transport carrier 10 is attracted to the table 111 by starting the DC power supply 126 . Specifically, the DC power supply 126 is activated to apply voltages with different polarities to the positive and negative electrodes of the ESC electrode 119 , thereby generating an adsorption force between the transport carrier 10 and the table 111 . Hereinafter, the present embodiment will be described with an example in which the ESC electrode 119 is bipolar, but it is not limited thereto.

FIG. 3 schematically shows the relationship between the bipolar ESC electrode 119 and the DC power supply 126 . The ESC electrodes 119 are, for example, comb electrodes shown in FIG. 3 . In FIG. 3 , a voltage of V1 is applied to the positive electrode, and a voltage of -V1 is applied to the negative electrode. The shape of the ESC electrode 119 is not limited thereto, and may be appropriately selected.

In addition, in the case of the fourth embodiment to the sixth embodiment, the timing to start applying the voltage to the ESC electrode 119 is not particularly limited, and may be before the lifting operation M, may be during the lifting operation M, or may be After the lifting action M is finished. In either case, the wrinkle of the holding sheet 3 is eliminated by the lifting operation M, so that the holding sheet 3 can be adsorbed to the table 111 without any wrinkle.

In addition, in the case of the first embodiment to the third embodiment, when a voltage is applied to the ESC electrode 119 , an operation of increasing or decreasing the absolute value of the applied voltage is included. In other words, the voltage applied to the ESC electrode 119 is temporarily increased or decreased. The increase and decrease of the voltage includes, for example, n times (n≧1) switching to a pattern of voltage V _n , voltage W _n , and voltage V _n+1 in sequence. The absolute value of the voltage W _n is smaller than the absolute value of the voltage V _n and the absolute value of the voltage V _n+1 (|V _n |>|W _n |, |V _n+1 |>|W _n |), or Zero (| _Wn | ≥ 0). The absolute value of the voltage V _n+1 may be the same as the absolute value of the voltage V _n , or may be greater than the absolute value of the voltage V _n (|V _n |≤|V _n+1 |).

When the voltage applied to the ESC electrode 119 is increased or decreased, after the holding sheet 3 is attracted to the stage 111, it is weakly attracted (further detached), and then strongly attracted. During this process, the wrinkles of the retaining sheet 3 are eliminated. In other words, the wrinkles are alleviated by temporarily desorbing the holding sheet 3 adsorbed to the table 111 in the state where the wrinkles have been generated. When a higher voltage is applied again, the holding sheet 3 is attracted with the wrinkles removed. Wrinkles can be eliminated more easily by performing the suction and suction, that is, application of high voltage (V) and application of low voltage (W) (or no application).

The removal (relaxation) of wrinkles of the protective sheet 3 will be described in detail below.

When a high voltage (V) is applied to the ESC electrode 119 , an adsorption force is generated at the contact portion of the holding sheet 3 with the table 111 . At this time, the wrinkles in the vicinity of the contact portion of the holding sheet 3 with the worktable 111 are stretched by the suction force acting on the contact portion of the holding sheet 3 with the worktable 111. The contact portion of the table 111 is enlarged. Next, a low voltage (W) is applied (or not applied) to the ESC electrode 119 . Thereby, the adsorption force of the holding piece 3 with respect to the table 111 is relieved. At this time, although the above-mentioned suction force is relaxed, the holding piece 3 maintains a shape in which the contact portion with the table 111 is enlarged. Next, if the high voltage (V) is applied to the ESC electrode 119 again, the suction force acts on the enlarged contact portion, so that the wrinkles near the enlarged contact portion are stretched, and the connection between the holding sheet 3 and the worktable The contact part of 111 is further expanded. By repeating the above, the wrinkles of the holding sheet 3 are relaxed.

In addition, the high voltage (V) to be applied to the ESC electrode 119 first is preferably a voltage whose absolute value is smaller than or equal to the absolute value of the high voltage (V) to be applied next. The reason for this is that if the absolute value of the high voltage (V) initially applied to the ESC electrode 119 is large, the effect of stretching the wrinkle may be difficult to appear. That is, it is preferable to apply a voltage with a small absolute value as the high voltage (V) applied to the ESC electrode 119 initially, and gradually expand the contact portion of the holding sheet 3 with the table 111 by repeating weaker adsorption and relaxation. , to eliminate wrinkles. The absolute value of the high voltage (V) can also be increased slowly.

The voltage increase and decrease may be performed multiple times. The number of times to increase or decrease is not particularly limited, and may be, for example, 2 to 5 times. It should be noted that the primary voltage increase and decrease refers to a pattern including, for example, V _n →W _n →V _n+1 . The voltage increase and decrease twice refers to a pattern including, for example, V _n →W _n →V _n+1 →W _n +1 →V _n +2. The period from the start of voltage application to the ESC electrode 119 until the plasma processing is performed includes at least one operation of increasing or decreasing the voltage. For example, the voltage may be applied to the ESC electrode 119 so as to include a pattern of V _n →W _n →V _n+1 at least once during the period from the start of voltage application to the ESC electrode 119 until the plasma processing is performed.

After performing a predetermined number of voltage increase and decrease operations, the applied voltage is adjusted so that the ESC electrode 119 becomes a predetermined voltage, and plasma processing is performed. The predetermined voltage, that is, the voltage of the ESC electrode 119 during plasma processing is not particularly limited, and may be higher than _Vn , for example. Hereinafter, the operation of applying a voltage to the ESC electrode 119 so as to include at least one voltage increase and decrease (in other words, a pattern including at least one _Vn → _Wn →Vn ₊₁ ) is referred to as variation application I.

Hereinafter, the first to third embodiments will be described in detail. In addition, this invention is not limited to this embodiment, Various changes are possible.

(first embodiment)

In this embodiment, the variation application I is performed in the pattern shown in FIG. 4 . That is to say, the voltage (V) of the ESC electrode 119 is set according to V1(V ₁ )→0V(W ₁ )→V1(V ₂ )→0V(W ₂ )→V1(V ₃ )→0V(W ₃ )→ V1 (V ₄ ) (n=4) increases and decreases. This pattern is performed, for example, by repeatedly turning on (ON)/off (OFF) the DC power supply 126 (see FIG. 6B ). FIG. 4 is a schematic graph in which the time from when the supporting portion 122 starts to descend is taken as the horizontal axis, and the voltage applied to the ESC electrode 119 is taken as the vertical axis.

In FIG. 4 , the descent start is the moment when the support portion 122 supporting the transport carrier 10 starts to descend. The bottoming start is when the lower end of the curved portion (curved portion) of the holding piece held on the conveyance carrier 10 comes into contact with the surface of the table 111 . The end of bottoming is the time when the upper end surface of the support portion 122 falls below the same level as the table 111 and (at least a part of) the outer peripheral portion 3c of the holding piece 3 comes into contact with the table 111 .

Whether or not the lower end of the bent portion of the holding piece 3 is in contact with the table 111 is judged, for example, by the distance D that the upper end surface 122 a of the support portion 122 descends. The deflection Tc of the holding piece 3 held by the conveyance carrier 10 is measured in advance (refer to later description), and the descending distance D of the support part 122 when the distance T between the upper end surface 122a of the support part 122 and the table 111 becomes Tc is grasped. Then, the time when the descending distance of the support portion 122 becomes D is regarded as the time when the curved portion of the holding piece 3 held by the transport carrier 10 first comes into contact with the table 111 .

The bending Tc is obtained, for example, as follows. As shown in FIG. 5 , the conveyance carrier 10 is placed on the upper end surface 122 a of the support portion 122 raised to the extent that the holding piece 3 does not come into contact with the table 111 . At this time, in a section passing through the center of the conveyance carrier 10, the shortest distance between a straight line L1 passing through the bottom surface 3b of the outer peripheral portion 3c of the holding piece 3 and a tangent line L2 to the bottom surface 3b of the lowermost point of the curved portion of the holding piece 3 is set to be Bend Tc.

The bending Tc does not necessarily need to be measured in the reaction chamber 103 or the plasma processing apparatus 100 . For example, before performing the processing in the plasma processing apparatus 100, it may be measured in advance by a non-contact optical measuring device or the like. In addition, in FIG. 5, in order to understand description easily, the curve Tc is emphasized and shown. When the diameter of the frame 2 is about 300 mm, the diameter of the substrate 1 is about 150 mm, the thickness of the substrate 1 is about 100 μm, and the thickness of the holding sheet 3 is about 110 μm, the bending Tc is, for example, about 50 μm to 800 μm.

In FIG. 4 , the voltage applied to the ESC electrode 119 is temporarily set to 0 (V) (W _n =0). The voltage W _n is not particularly limited as long as its absolute value is smaller than the absolute value of the voltage V _n and the absolute value of the voltage V _n+1 . For example, the voltage _Wn may have a polarity opposite to that of the voltage _Vn and/or the voltage Vn ₊₁ . Among them, the voltage W _n is preferably 0 (V) from the viewpoint of suppressing residual adsorption.

Variation application I will be described with reference to FIGS. 6A and 6B . FIG. 6A schematically shows the state from when the support portion 122 supporting the transport carrier 10 starts to descend until the transport carrier 10 is mounted on the table 111 . FIG. 6B is a schematic diagram showing a state in which variation I is applied. For easy understanding, in FIGS. 6A and 6B , the ESC electrodes 119 to which a voltage is applied are hatched and shown. In addition, also in FIGS. 6A and 6B , for the sake of explanation, the curves are emphasized and shown in the drawings.

As shown in FIG. 6A(a), first, the support portion 122 supporting the transport carrier 10 starts to descend. At this time, the distance T between the upper end surface 122a of the support part 122 and the table 111 is greater than the bending Tc (T>Tc). The supporting portion 122 continues to descend, and the lower end of the bent portion of the holding piece 3 contacts the table 111 ( FIG. 6A( b ), T=Tc). Thereafter, the support portion 122 also continues to descend ( FIG. 6A( c )), and the bottoming of the holding piece 3 is completed ( FIG. 6A( d )).

After the bottoming of the holding sheet 3 is completed ( FIG. 6A( d )), the variable application I is performed ( FIGS. 6B( a ) to ( d )). The variation application I is performed in a state where at least a part of the outer peripheral portion 3 c of the holding piece 3 is in contact with the table 111 . At this time, the entire outer peripheral portion 3 c may be brought into contact with the table 111 . A constant voltage (for example, V1 ) may be applied to the ESC electrode 119 until the bottoming of the holding sheet 3 is completed (T>0), that is, during the period of FIGS. 6A( a ) to ( c ).

When the holding sheet 3 is in contact with the table 111 in a wrinkled state, when the voltage V1 is applied, the holding sheet 3 is attracted to the table 111 while maintaining the original state. Next, when a voltage W1 lower than V1 is applied to the ESC electrode, the adsorption force between the contact portion of the protective sheet 3 with the table 111 and the table 111 becomes small. Therefore, wrinkles generated in the contact portion of the holding sheet 3 with the table 111 are temporarily relieved. Then, when the voltage V1 is applied again, the holding sheet 3 is sucked in a state where wrinkles are removed. Wrinkles are easier to eliminate by applying I repeatedly. Then, the substrate 1 is uniformly etched by performing plasma processing with a predetermined voltage applied to the ESC electrode 119 .

Hereinafter, the operation of the plasma processing apparatus 100 will be specifically described with reference to FIG. 7 . In addition, in FIG. 7 also, for explanation, the curve is emphasized and shown.

In the vacuum chamber 103 , in order to support the conveyance carrier 10 , the standby is performed with the plurality of support parts 122 raised. The outer cover 124 also stands by at the raised position ( FIG. 7( a )). The transport carrier 10 is transported into the vacuum chamber 103 by a transport mechanism not shown, and delivered to a plurality of support parts 122 ( FIG. 7( b )).

The transport carrier 10 is placed on the upper end surface 122a of the support portion 122 such that the surface of the holding sheet 3 holding the substrate 1 (adhesive surface 3a ) faces upward. The frame 2 may be placed on the upper end surface 122a of the supporting part 122 via the outer peripheral part 3c of the holding piece 3, or may be placed directly on the upper end surface 122a of the supporting part 122. From the viewpoint of suppressing peeling between the frame 2 and the holding sheet 3 during the lifting operation of the supporting section 122, it is preferable that the transport carrier 10 is placed on the upper end surface of the supporting section 122 with the outer peripheral portion 3c of the holding sheet 3 interposed therebetween. 122a.

Next, the support portion 122 descends ( FIG. 7( c )). Furthermore, when the support part 122 continues to descend, the outer peripheral part 3c of the holding piece 3 will contact the table 111, and the conveyance carrier 10 will be mounted on the predetermined position of the table 111 (FIG.7(d)). When the upper end surface 122a of the support part 122 falls below the same level as the table 111, it can be judged that the outer peripheral part 3c of the holding piece 3 is in contact with the table 111. FIG.

Variation application I is performed in the state of FIG. 7( d ) (see FIG. 6B ). After the variation application I is completed, the lifting rod 121 is driven by the lifting mechanism 123B to lower the cover 124 to a predetermined position ( FIG. 7( e )).

In addition, when the ESC electrode 119 is a monopole, the transport carrier 10 is placed on the upper end surface 122a of the support portion 122 by the transport mechanism, and after the transport mechanism withdraws from the vacuum chamber 103, until the voltage is applied to the ESC electrode 119 Until now, low power (for example, 500 W or less) is supplied to the antenna 109 from the first high-frequency power supply 110A, and plasma is generated in the reaction chamber 103 . Thereby, the surface of the transport carrier 10 is charged, and the transport carrier 10 can be attracted to the stage 111 simultaneously with the voltage being applied to the ESC electrode 119 .

When the cover 124 is arranged at a predetermined lowered position, the parts of the frame 2 and the holding piece 3 that do not hold the substrate 1 are covered by the cover 124 without contacting the cover 124 , and the substrate 1 is exposed from the window 124W of the cover 124 .

The portion of the cover 124 excluding the end portion is, for example, an annular shape having a substantially circular outline, and has a constant width and a relatively thin thickness. The inner diameter of the portion of the cover 124 excluding the end (the diameter of the window portion 124W) is smaller than the inner diameter of the frame 2 , and the outer diameter of the portion of the cover 124 excluding the end is larger than the outer diameter of the frame 2 . Therefore, when the transport carrier 10 is mounted at a predetermined position on the table 111 and the cover 124 is lowered, the cover 124 can cover at least a part of the frame 2 and the holding piece 3 . At least a part of the substrate 1 is exposed through the window portion 124W. At this time, the cover 124 is not in contact with any of the frame 2 , the holding piece 3 and the substrate 1 . The cover 124 is made of, for example, ceramics (for example, alumina, aluminum nitride, etc.), dielectrics such as quartz, or metals such as aluminum or aluminum whose surface has been treated with an alumina film.

When the support portion 122 and the cover 124 are arranged at predetermined positions, the process gas is introduced into the vacuum chamber 103 from the process gas source 112 through the gas introduction port 103a. On the other hand, the decompression mechanism 114 exhausts the gas in the vacuum chamber 103 through the exhaust port 103b, and maintains the inside of the vacuum chamber 103 at a predetermined pressure.

Next, high-frequency power is supplied to the antenna 109 from the first high-frequency power supply 110A, and plasma P is generated in the vacuum chamber 103 . The generated plasma P is composed of ions, electrons, radicals and the like. Next, high-frequency power is supplied to the high-frequency electrode 120 from the second high-frequency power supply 110B, and plasma processing on the substrate 1 is started. Incident energy of ions to the substrate 1 can be controlled by a bias voltage applied from the second high-frequency power supply 110B to the high-frequency electrode 120 . The portion exposed from the resist mask formed on the substrate 1 is removed from the front to the back by a physicochemical reaction with the generated plasma P, and the substrate 1 is singulated.

The conditions of the plasma processing are set according to the material of the substrate 1 and the like. For example, when the substrate 1 is Si, the substrate 1 is etched by generating plasma P of a fluorine-containing gas such as sulfur hexafluoride (SF ₆ ) in the vacuum chamber 103 . In this case, for example, SF ₆ gas is supplied from the process gas source 112 at 100 to 800 sccm, and the pressure of the reaction chamber 103 is controlled to 10 to 50 Pa by the decompression mechanism 114 . High-frequency power of 1000 to 5000 W and a frequency of 13.56 MHz is supplied to the antenna 109 , and high-frequency power of 50 to 1000 W and a frequency of 13.56 MHz is supplied to the high-frequency electrode 120 . At this time, the temperature of the refrigerant circulating in the table 111 is set to -20 to 20° C. by the refrigerant circulation device 125 in order to suppress the temperature rise of the transport carrier 10 due to the plasma treatment. Accordingly, the temperature of the transport carrier 10 during the plasma treatment can be suppressed to 100° C. or lower.

During the etching process, the surface of the substrate 1 exposed from the resist mask is preferably etched vertically. In this case, for example, an etching step using plasma of a fluorine-based gas such as SF ₆ and a protective film deposition step using plasma of a fluorinated carbon gas such as octafluorocyclobutane (C ₄ F ₈ ) may be alternately repeated.

After the plasma P is generated, the operation mode of the ESC electrode 119 may be switched from the bipolar mode to the unipolar mode. Under the situation that the mode of operation of ESC type electrode 119 is bipolar mode, the surface (positive electrode side surface) of the substrate 1 of the top of the positive pole of ESC type electrode 119 and the surface of the substrate 1 of the top of the negative pole of ESC type electrode 119 ( negative side surface), the potential is slightly different. In addition, since the Coulomb force on the positive electrode side is stronger than that on the negative electrode side, the adsorption force is also slightly different.

Therefore, if the plasma processing is started in the state of the bipolar mode, the difference in the temperature of the substrate 1 due to the difference in the adsorption force of the table 111 will occur between the positive electrode side surface and the negative electrode side surface of the ESC type electrode 119. . In addition, there may be a difference in the effective bias voltage applied to the substrate 1 between the surface on the positive electrode side and the surface on the negative electrode side. Furthermore, there may be a difference in the degree of etching between the positive electrode side surface and the negative electrode side surface. For these reasons, it may be difficult to perform uniform plasma processing on the substrate 1 .

Switching from the bipolar mode to the unipolar mode is performed by, for example, reversing the polarity of the voltage applied to the positive or negative pole, or changing the voltage applied to the positive or negative pole to the voltage of the other. The same is done by waiting.

When switching from the bipolar mode to the unipolar mode, the adsorption force of the transport carrier 10 to the table 111 is momentarily weakened, and the cooling of the transport carrier 10 may become insufficient. Therefore, switching from the dipole mode to the monopole mode is preferably performed while low power (for example, 500 W or less) is applied to the antenna 109 from the first high-frequency power supply 110A.

In other words, first, low power is supplied to the antenna 109 from the first high frequency power supply 110A to generate low power plasma, and the operation mode of the ESC electrode 119 is switched from the bipolar mode to the monopolar mode. After this switching is completed, it is preferable to input high power from the first high-frequency power supply 110A to the antenna 109 to perform plasma processing (see FIG. 8( c )). When the input power to the antenna 109 is low, the energy of the generated plasma is weak, and therefore the amount of heat conducted from the plasma to the transport carrier 10 is small. Therefore, it is less necessary to strongly adsorb and cool the transport carrier 10 to the table 111 . Therefore, at the time of switching from the bipolar mode to the unipolar mode, defects due to insufficient cooling of the transport carrier 10 are less likely to occur.

The voltage applied to each ESC electrode 119 may be increased between switching to the unipolar mode and starting the plasma treatment. 8( a ) and ( b ) show schematic graphs in which the time from the first high-frequency power supply 110A power supply to the antenna 109 is taken as the horizontal axis, and the voltage applied to each ESC electrode 119 is shown as the vertical axis. As shown in Figure 8 (a) and (b), after switching to the unipolar mode, the applied voltage to each ESC electrode 119 is gradually increased to +V2, and the adsorption of the transport carrier 10 to the worktable 111 is sufficiently improved. . Then, high power is applied to the antenna 109 from the first high-frequency power supply 110A, and plasma processing starts.

Specifically, for example, in the bipolar mode, the positive voltage (+V1) is 1500V, the negative voltage (-V1) is -1500V, and the input power (low power) of the antenna 109 is 500W. Next, switch from the bipolar mode to the unipolar mode by changing the negative electrode voltage (-V1) from -1500V to 1500V. Then, both the positive electrode voltage (+V1) and the negative electrode voltage (−V1) were increased stepwise to 3000V (+V2). Finally, the input power (high power) to the antenna 109 is increased to 2000W to 5000W, and plasma processing is performed. Thereby, it is possible to suppress the generation of defects accompanying switching from the bipolar mode to the unipolar mode, and also during plasma processing, the carrier 10 can be strongly adsorbed to the table 111, and the carrier 10 can be reliably cooled. .

After singulation, ashing is performed. A process gas for ashing (for example, oxygen, a mixed gas of oxygen and a gas containing fluorine, etc.) is introduced into the vacuum chamber 103 from an ashing gas source 113 . On the other hand, exhaust is performed by the decompression mechanism 114 to maintain the inside of the vacuum chamber 103 at a predetermined pressure. Oxygen plasma is generated in the vacuum chamber 103 by inputting high-frequency power from the first high-frequency power supply 110A, and the resist mask on the surface of the substrate 1 (chip) exposed through the window portion 124W of the cover 124 is completely removed.

Finally, the transport carrier 10 holding the singulated substrates 1 is carried out from the plasma processing apparatus 100 . The unloading of the substrate 1 may be performed in the reverse order of the procedure of loading the substrate 1 on the table 111 shown in FIG. 7 . That is, after raising the cover 124 to a predetermined position, the voltage applied to the ESC electrode 119 is set to zero, the suction of the transport carrier 10 to the table 111 is released, and the supporting part 122 is raised. In the case where the electric charge during the plasma treatment remains in the transport carrier 10 and the transport carrier 10 remains and is adsorbed on the workbench 111, it is also possible to switch from the first high-frequency power source before or during the ascent of the supporting part 122 as needed. 110A injects weak high-frequency power of, for example, about 200 W into the antenna 109 to generate weak plasma to eliminate static electricity on the transport carrier 10 .

(second embodiment)

This embodiment is the same as the first embodiment except for including a pattern in which the voltage _{Vn +1} is higher than the voltage Vn. In other words, in this embodiment, as the increase and decrease operation is repeated, the absolute value of the high voltage (V _n+1 ) applied after the low voltage (W _n ) is made larger than the high voltage (V _n ) applied before. Big. FIG. 9 shows a pattern of variation application I in this embodiment. In Figure 9, make the voltage (V) of the ESC electrode follow V1(V ₁ )→0V(W ₁ )→V2(V ₂ , V2>V1)→0V(W ₂ )→V3(V ₃ , V3>V2 )→0V(W ₃ )→V3(V ₄ )(n=4) changes. This pattern is performed, for example, by repeating twice as follows: after the DC power supply 126 is adjusted so that after the DC power supply 126 is disconnected (OFF), a voltage higher than the voltage before the disconnection is applied, and then the DC power supply 126 is turned on (ON). .

FIG. 9 is a schematic graph in which the time from when the supporting portion 122 starts to descend is taken as the horizontal axis, and the voltage applied to the ESC electrode 119 is taken as the vertical axis. As shown in FIG. 9 , by including a pattern in which the applied voltage is gradually increased, the holding sheet 3 is attracted to the table 111 in a state where wrinkles are further eliminated. When the voltage applied to the ESC electrode 119 is high, the holding sheet 3 has a large adsorption force with respect to the table 111 . Wrinkles that cannot be eliminated under the situation of weak voltage adsorption are temporarily released (or after weakening), and by applying a larger voltage to the ESC electrode 119, a larger adsorption force acts on the holding sheet 3, so it can be is eliminated.

(third embodiment)

This embodiment is the same as the first embodiment except that a pattern for inverting the polarities of the voltage _Vn and the voltage Vn ₊₁ is included. In other words, in this embodiment, when the increase and decrease operations are repeated, the polarity of the high voltage (V _n+1 ) applied after the low voltage (W _n ) is different from the polarity of the high voltage (V _n ) applied before. on the contrary. FIG. 10 shows the pattern of the variation application I in this embodiment. In FIG. 10, a voltage of the ESC electrode 119 is set according to V1(V ₁ )→0V(W ₁ )→-V1(V ₂ )→0V(W ₂ )→V1(V ₃ )→0V(W ₃ )→ V1 (V ₄ ) (n=4) increases and decreases. This pattern is performed by repeating ON/OFF of the DC power supply 126 three times, for example, using a polarity inversion switch. FIG. 10 is a schematic graph in which the time from when the supporting portion 122 starts to descend is taken as the abscissa, and the voltage applied to one of the ESC electrodes 119 is taken as the ordinate.

By reversing the polarity of the applied voltage, the portion corresponding to the positive electrode and the portion corresponding to the negative electrode of the ESC electrode of the substrate 1 are switched. Therefore, residual suction is reduced, and the relaxation of wrinkles of the holding sheet 3 when the DC power supply 126 is turned off (OFF) becomes greater. Therefore, the wrinkles of the retaining sheet 3 are more easily eliminated.

Next, the fourth to sixth embodiments will be described in detail. In addition, this invention is not limited to this embodiment, Various changes are possible.

(fourth embodiment)

In the present embodiment, after the voltage application to the ESC electrode 119 is started, the raising and lowering operation M is performed. FIG. 11( a ) shows a schematic graph in which the time from when the supporting portion 122 starts to descend is taken as the horizontal axis, and the voltage applied to the ESC electrode 119 is taken as the vertical axis. FIG. 11( b ) shows a schematic graph in which the time from when the support part 122 starts to descend is taken as the horizontal axis, and the distance T between the upper end surface 122 a of the support part 122 and the table 111 is taken as the vertical axis.

In FIGS. 11( a ) and 11 ( b ), the start of descent is when the support portion 122 supporting the transport carrier 10 starts to descend. The bottoming start is when the lowest point of the curved portion (curved portion) of the holding sheet 3 held on the conveyance carrier 10 first comes into contact with the table 111 . The end of bottoming is when the upper end surface 122 a of the support portion 122 falls below the same level as the surface of the table 111 and the outer peripheral portion 3 c of the holding piece 3 comes into contact with the table 111 .

Whether or not the bent portion of the holding piece 3 is in contact with the table 111 is determined, for example, by the distance D that the upper end surface 122 a of the support portion 122 descends. The deflection Tc of the holding piece 3 held by the conveyance carrier 10 is measured in advance (see later), and the descending distance of the support portion 122 when the distance T between the upper end surface 122a of the support portion 122 and the surface of the table 111 becomes Tc is grasped. d. Then, the time when the descending distance of the support portion 122 becomes D is regarded as the time when the lowest point of the curved portion of the holding piece 3 held by the conveyance carrier 10 first comes into contact with the table 111 .

The bending Tc is obtained, for example, as follows. As shown in FIG. 5 , the conveyance carrier 10 is placed on the upper end surface 122 a of the support portion 122 raised to the extent that the holding piece 3 does not come into contact with the table 111 . At this time, in a section passing through the center of the conveyance carrier 10, the shortest distance between a straight line L1 passing through the bottom surface 3b of the outer peripheral portion 3c of the holding piece 3 and a tangent line L2 to the bottom surface 3b of the lowermost point of the curved portion of the holding piece 3 is set to be Bend Tc.

The bending Tc does not necessarily need to be measured in the reaction chamber 103 or the plasma processing apparatus 100 . For example, before performing the processing in the plasma processing apparatus 100, it may be measured in advance by a non-contact optical measuring device or the like. In addition, in FIG. 5, in order to understand description easily, the curve Tc is emphasized and shown. When the diameter of the frame 2 is about 300 mm, the diameter of the substrate 1 is about 150 mm, the thickness of the substrate 1 is about 100 μm, and the thickness of the holding sheet 3 is about 110 μm, the bending Tc is, for example, about 50 μm to 800 μm.

In FIG. 11 , after the application is started, the bottoming of the holding sheet 3 starts, and the lifting operation M is performed until the bottoming is completed. The timing of the lifting operation M is not limited thereto. For example, the lifting operation M may be performed by raising the support portion 122 again after the holding piece 3 temporarily touches the bottom.

The lifting operation M will be described with reference to FIGS. 12A and 12B . FIG. 12A schematically shows the state from when the support portion 122 supporting the transport carrier 10 starts to descend until the transport carrier 10 is mounted on the table 111 . FIG. 12B schematically shows the situation of the lifting motion M. In FIGS. 12A and 12B , the ESC electrodes 119 to which a voltage is applied are shown by hatching. In addition, in FIGS. 12A and 12B also, for the sake of explanation, the curves are emphasized and shown.

As shown in FIG. 12A(a), first, the support portion 122 supporting the transport carrier 10 starts to descend. At this time, the distance T between the upper end surface 122a of the support part 122 and the table 111 is greater than the bending Tc (T>Tc). A voltage is applied to the ESC electrode 119 after the lowering of the supporting portion 122 starts. The support portion 122 continues to descend, and the contact portion is attracted to the table 111 while the lowermost point of the bent portion of the holding piece 3 contacts the table 111 (T=Tc) ( FIG. 12A(b) ). Thereafter, the contact portion of the holding piece 3 with the table 111 is also immediately attracted to the table 111 ( FIG. 12A( c )), and bottoming is completed ( FIG. 12A( d )).

The lifting operation M is performed after the bottoming of the holding piece 3 ( FIG. 12A( c )) and until the bottoming is completed ( FIG. 12A( d )) (see FIGS. 12B( a ) to ( d )). The raising and lowering operation M is an operation in which the support portion 122 lowered from the delivery position to the loading position is raised in the vicinity of the table 111 once, and then lowered again. Here, the following action is repeated twice (Fig. 12B(c), (d)): after the supporting part 122 is raised to the distance T=Tc (Fig. 12B(a)), it is lowered so that 0<T< Tc (FIG. 12B(b)). The raising and lowering operation M may be performed multiple times (for example, 2 to 3 times) with the raising and lowering of the support part 122 being one cycle.

Since a voltage is applied to the ESC electrode 119 , an attracting force acts from the table 111 to the contact portion of the holding sheet 3 with the table 111 . Therefore, the holding sheet 3 is attracted to the table 111 while being in contact with the table 111 . At this time, the holding sheet 3 may be sucked in a wrinkled state. By raising and lowering operation M, wrinkles can hardly be generated at the contact portion of the holding sheet 3 with the table 111 .

Specifically, the raising and lowering operation M is an operation of temporarily raising the support portion 122 after the holding piece 3 bottoms out, and then lowering the support portion 122 again. The transport carrier 10 is separated from the table 111 by raising the support part 122 . Wrinkles of the holding sheet 3 are temporarily eliminated by the lifting operation of the support portion 122 . In the lifting operation M, the supporting part 122 can rise to a position where the holding piece 3 maintains contact with the worktable 111 , and can also rise to a position where it does not contact. In the raising and lowering operation M, the supporting portion 122 is lowered at least to a position where the bent portion of the holding piece 3 contacts the table 111 .

When the supporting portion 122 is raised, tension is applied from the frame 2 to the holding sheet 3 to stretch the wrinkled portion and the non-absorbed portion of the holding sheet 3 . Then, when the support part 122 is lowered again, the curved part first comes into contact with the table 111, and is adsorbed to the table 111 while contacting again. Furthermore, the area surrounding the curved portion comes into contact with the table 111 again, and is electrostatically attracted while being in contact again. At this time, the portion of the holding sheet 3 that was wrinkled in the previous upward movement and the portion that was not sucked is stretched. Therefore, the holding sheet 3 tends to follow the surface of the table 111 (adhesion is easy), and the contact portion of the holding sheet 3 with the table 111 expands. Through such lifting operation M, wrinkles generated in the contact portion of the holding sheet 3 with the table 111 are eliminated. Therefore, the holding sheet 3 is adsorbed to the table 111 without wrinkles. Then, the substrate 1 is uniformly etched by performing plasma treatment.

The lifting operation M is performed in a state where the upper end surface 122 a of the support portion 122 is in the vicinity of the surface of the table 111 . In the raising and lowering operation M, the upper end surface 122a of the support part 122 moves up and down between 0.1 mm and 5 mm from the surface of the table 111 . Its amplitude is preferably, for example, equal to or smaller than bending Tc. In addition, when lifting and lowering is performed a plurality of times in the lifting and lowering operation M, the amplitude may be reduced every time the number of times of lifting and lowering increases.

As shown in FIG. 12B , the lifting operation M may be performed with at least a part of the holding piece 3 in contact with the table 111 . Wrinkles of the holding sheet 3 are further easily removed by performing the lifting operation M with a part of the holding sheet 3 as a support point. At this time, the lowering of the supporting part 122 in the lifting operation M can be performed until the upper end surface 122a of the supporting part 122 becomes the same level as the surface of the table 111 (T=0), and can also be performed within the range of 0<T<Tc .

Hereinafter, the operation of plasma processing apparatus 100 will be specifically described with reference to FIG. 13 . In addition, also in FIG. 13, for the sake of explanation, the bending is emphasized and shown.

In the vacuum chamber 103 , in order to support the conveyance carrier 10 , the plurality of support parts 122 stand by in a raised state. The housing 124 is also on standby at the raised position ( FIG. 13( a )). The transport carrier 10 is transported into the vacuum chamber 103 by a transport mechanism not shown, and delivered to a plurality of support parts 122 ( FIG. 13( b )).

The transport carrier 10 is placed on the upper end surface 122a of the support portion 122 such that the surface of the holding sheet 3 holding the substrate 1 (adhesive surface 3a ) faces upward. The frame 2 may be placed on the upper end surface 122a of the support portion 122 via the outer peripheral portion 3c of the holding piece 3 , or the frame 2 may be placed directly on the upper end surface 122a of the support portion 122 . From the viewpoint of suppressing peeling between the frame 2 and the holding sheet 3 during the lifting operation of the supporting section 122, it is preferable that the transport carrier 10 is placed on the upper end surface of the supporting section 122 with the outer peripheral portion 3c of the holding sheet 3 interposed therebetween. 122a.

Next, the support portion 122 descends ( FIG. 13( c )). The DC power supply 126 starts applying a voltage to the ESC electrodes 119 after the transport carrier 10 is delivered to the support portion 122 and until a part of the holding sheet 3 comes into contact with the table 111 .

In addition, when the ESC electrode 119 is a monopole, the transport carrier 10 is placed on the upper end surface 122a of the support portion 122 by the transport mechanism, and after the transport mechanism withdraws from the vacuum chamber 103, until the voltage is applied to the ESC electrode 119 During the period, low power (for example, 500 W or less) is input to the antenna 109 from the first high-frequency power supply 110A, and plasma is generated in the reaction chamber 103 . Thereby, the surface of the transport carrier 10 is charged, and the transport carrier 10 can be attracted to the stage 111 simultaneously with the voltage being applied to the ESC electrode 119 .

Furthermore, when the support part 122 continues to descend, the outer peripheral part 3c of the holding piece 3 will contact the table 111, and the conveyance carrier 10 will be mounted on the predetermined position of the table 111 (FIG.13(d)). When the upper end surface 122a of the support part 122 falls below the same level as the table 111, it can be judged that the outer peripheral part 3c of the holding piece 3 is in contact with the table 111. FIG. Between Fig. 13(c) and Fig. 13(d), the lifting operation M shown in Fig. 12B is performed.

When the lifting operation M is completed, the upper end surface 122a of the support portion 122 is lowered below the same level as the table 111, and the loading of the transport carrier 10 is completed. Then, the elevating rod 121 is driven by the elevating mechanism 123B to lower the cover 124 to a predetermined position ( FIG. 13( e )). When the cover 124 is arranged at a predetermined lowered position, the parts of the frame 2 and the holding piece 3 that do not hold the substrate 1 are covered by the cover 124 without contacting the cover 124 , and the substrate 1 is exposed from the window 124W of the cover 124 .

When the support portion 122 and the cover 124 are arranged at predetermined positions, the process gas is introduced into the vacuum chamber 103 from the process gas source 112 through the gas introduction port 103a. On the other hand, the decompression mechanism 114 exhausts the gas in the vacuum chamber 103 through the exhaust port 103b, and maintains the inside of the vacuum chamber 103 at a predetermined pressure.

Next, high-frequency power is supplied to the antenna 109 from the first high-frequency power supply 110A, and plasma P is generated in the vacuum chamber 103 . The generated plasma P is composed of ions, electrons, radicals and the like. Next, high-frequency power is supplied to the high-frequency electrode 120 from the second high-frequency power supply 110B, and plasma processing on the substrate 1 is started. The incident energy of ions on the substrate 1 can be controlled by the bias voltage applied from the second high-frequency power supply 110B to the high-frequency electrode 120 . The portion exposed from the resist mask formed on the substrate 1 is removed from the front to the back by a physicochemical reaction with the generated plasma P, and the substrate 1 is singulated. In addition, the steps from singulation to unloading of the transport carrier 10 may be performed in the same manner as in the first embodiment.

(fifth embodiment)

This embodiment is the same as the fourth embodiment except that voltage application to the ESC electrode 119 is started while the lifting operation M is being performed. FIG. 14( a ) shows a schematic graph in which the time from when the supporting portion 122 starts to descend is taken as the horizontal axis, and the voltage applied to the ESC electrode 119 is taken as the vertical axis. FIG. 14( b ) shows a schematic graph in which the time from when the support part 122 starts to descend is taken as the horizontal axis, and the distance T between the upper end surface 122 a of the support part 122 and the table 111 is taken as the vertical axis.

In FIG. 14 , the lifting operation M is performed between the start of bottoming of the holding piece 3 and the end of bottoming. The timing of the raising and lowering operation M is not limited thereto. For example, the raising and lowering operation M may be performed by raising the support portion 122 again after the bottoming of the temporary holding sheet 3 is completed.

According to the present embodiment, through the lifting operation M, the bent portion of the holding piece 3 can be tightened and brought into contact with the table 111 . Then, by quickly starting the voltage application, the bent portion, which is prone to wrinkles, is attracted to the table 111 without wrinkles. Furthermore, by performing the lifting operation M with the bent portion to be sucked as a support point, suction can be performed while removing other wrinkles. Then, the substrate 1 is uniformly etched by performing plasma treatment.

(sixth embodiment)

This embodiment is the same as the fourth embodiment except that voltage application to the ESC electrode 119 is started after the lifting operation M is performed. FIG. 15( a ) shows a schematic graph in which the time from when the supporting portion 122 starts to descend is taken as the horizontal axis, and the voltage applied to the ESC electrode 119 is taken as the vertical axis. FIG. 15( b ) shows a schematic graph in which the time from when the support part 122 starts to descend is taken as the horizontal axis, and the distance T between the upper end surface 122 a of the support part 122 and the table 111 is taken as the vertical axis.

In FIG. 15 , the lifting operation M is performed between the start of bottoming of the holding piece 3 and the end of bottoming. The timing of the raising and lowering operation M is not limited thereto. For example, the raising and lowering operation M may be performed by raising the support portion 122 again after the bottoming of the temporary holding sheet 3 is completed. The holding sheet 3 can be brought into tight contact with the table 111 by the lifting operation M, and then the holding sheet 3 can be attracted to the table 111 without wrinkles by quickly applying a voltage.

Industrial availability

The plasma processing apparatus of the present invention is useful as an apparatus for performing plasma processing on a substrate held on a transport carrier.

Claims (14)

1. A plasma processing device for performing plasma processing on a substrate held on a transport carrier, The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, the substrate is held by the holding sheet, The plasma processing device has: reaction chamber; a plasma generating unit that generates plasma in the reaction chamber; a workbench, which is configured inside the reaction chamber and used to carry the transport carrier; An electrostatic adsorption mechanism having an electrode part provided inside the workbench; a support portion that supports the conveyance carrier between a loading position on the workbench and a handover position detached upward from the workbench; and an elevating mechanism that elevates the support portion relative to the workbench, When the transport carrier is mounted on the table, the electrostatic adsorption mechanism applies a voltage to the electrode portion after the outer peripheral portion of the holding piece comes into contact with the table, The application of the voltage includes an operation of increasing or decreasing the absolute value of the voltage, The plasma generation part generates plasma after the operation ends. 2. The plasma processing apparatus according to claim 1, wherein, The increase or decrease is performed by sequentially switching the voltage to voltage V _n , voltage W _n , and voltage V _n+1 , where n is an integer greater than or equal to 1, |V _n |>|W _n |, |W _n |≥0 and | _Vn |≤|Vn ₊₁ |. 3. The plasma processing apparatus according to claim 2, wherein, The voltage V _n and the voltage V _n+1 satisfy the relationship of |V _n |<|V _n+1 |. 4. The plasma processing apparatus according to claim 2 or 3, wherein, The polarities of the voltage _Vn and the voltage Vn ₊₁ are reversed. 5. A plasma processing method, wherein a transport carrier holding a substrate is mounted on a workbench provided in a plasma processing apparatus, and the substrate is subjected to plasma processing, The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, the substrate is held by the holding sheet, The plasma treatment method includes: a step of supporting the conveyance carrier on a support portion that can be raised and lowered relative to the workbench at a handover position detached upward from the workbench; a step of lowering the support unit to mount the transport carrier at a mounting position on the table; and a step of applying a voltage to an electrode portion of an electrostatic adsorption mechanism provided inside the table, The step of applying a voltage to the electrode portion includes an operation of increasing or decreasing an absolute value of the voltage after the outer peripheral portion of the holding piece comes into contact with the table, After the operation is finished, the plasma treatment is performed. 6. The plasma processing method according to claim 5, wherein, The increase or decrease is performed by sequentially switching the voltage to voltage V _n , voltage W _n , and voltage V _n+1 , wherein, n≥1, |V _n |>|W _n |, |W _n |≥0 And | _Vn |≤|Vn ₊₁ |. 7. The plasma processing method according to claim 6, wherein, The voltage V _n and the voltage V _n+1 satisfy the relationship of |V _n |<|V _n+1 |. 8. The plasma processing method according to claim 6 or 7, wherein, The polarities of the voltage _Vn and the voltage Vn ₊₁ are reversed. 9. A plasma processing device for performing plasma processing on a substrate held on a transport carrier, The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, the substrate is held by the holding sheet, The plasma processing device has: reaction chamber; a plasma generating unit that generates plasma in the reaction chamber; a workbench, which is configured inside the reaction chamber and used to carry the transport carrier; An electrostatic adsorption mechanism having an electrode part provided inside the workbench; a support portion that supports the conveyance carrier between a loading position on the workbench and a handover position detached upward from the workbench; and an elevating mechanism that elevates the support portion relative to the workbench, When the transport carrier is mounted on the table, After the holding piece comes into contact with the workbench, the elevating mechanism raises and lowers the support part one or more times in the vicinity of the workbench, The plasma generation unit generates plasma after the ascent and descent of the support unit is completed and after the outer peripheral portion of the holding piece comes into contact with the table. 10. The plasma processing apparatus according to claim 9, wherein: The raising and lowering of the support portion are performed with at least a part of the holding piece in contact with the table. 11. The plasma processing apparatus according to claim 9 or 10, wherein, The electrostatic adsorption mechanism starts applying a voltage to the electrode portion before the outer peripheral portion of the holding piece comes into contact with the table. 12. A plasma processing method, wherein a transport carrier holding a substrate is mounted on a workbench provided in a plasma processing apparatus, and plasma processing is performed on the substrate, The transport carrier includes a holding sheet and a frame disposed on the outer periphery of the holding sheet, the substrate is held by the holding sheet, The plasma treatment method has: a step of supporting the conveyance carrier on a support portion that can be raised and lowered relative to the workbench at a handover position detached upward from the workbench; a step of lowering the support unit to mount the transport carrier at a mounting position on the table; and a step of applying a voltage to an electrode portion of an electrostatic adsorption mechanism provided inside the table, The step of mounting the conveyance carrier includes: raising and lowering the support part at least once in the vicinity of the workbench after the holding piece comes into contact with the workbench, The plasma treatment is performed after the raising and lowering of the supporting portion is completed, and after the outer peripheral portion of the holding piece comes into contact with the table. 13. The plasma processing method according to claim 12, wherein, The raising and lowering of the support portion are performed with at least a part of the holding piece in contact with the table. 14. The plasma processing method according to claim 12 or 13, wherein, Before the outer peripheral portion of the holding piece comes into contact with the stage, the voltage application to the electrode portion starts.